Stadler will present a new version of its FLIRT Akku battery multiple unit at InnoTrans 2026 in Berlin, the manufacturer has announced.

The Swiss rolling stock maker has confirmed the debut appearance of the updated FLIRT Akku at the trade fair, which opens its doors at the Messe Berlin exhibition grounds in September 2026. The company has not yet released full technical specifications for the vehicle, and details of the configuration on display remain to be confirmed closer to the event.

The FLIRT Akku family has an established track record in regional operation. The design pairs Stadler's FLIRT platform — in service with multiple European operators in electric and diesel variants — with battery traction, allowing passenger services to run on non-electrified lines without continuous overhead power. Trains charge their batteries from the overhead line where it exists and run on stored energy across gaps in the infrastructure, an approach that removes the cost of extending catenary over short unelectrified sections.

For regional operators, the operating logic is straightforward: battery multiple units can replace diesel sets on branch lines and secondary routes, cutting both emissions and energy costs while retaining the option to use existing electrified corridors for recharging in service. That flexibility has driven orders for battery trains across Germany in particular, where several operators have contracted for FLIRT Akku units to serve routes where full electrification does not justify the capital expenditure.

InnoTrans, held biennially in Berlin, has become the principal showcase for such vehicles, with recent editions featuring battery and hydrogen prototypes from most major European manufacturers. Stadler's decision to bring an updated FLIRT Akku to the 2026 edition signals that the company intends to keep the product competitive as rivals including Alstom, Siemens Mobility and CAF expand their own battery-equipped regional offerings.

Questions that remain open ahead of the launch include whether the new version offers increased battery capacity or range compared with the units already in service, and whether Stadler has secured launch customers for the updated design. The manufacturer is expected to publish technical data and fleet details at or before the September 2026 presentation.

InnoTrans 2026 runs from 22 to 25 September 2026 in Berlin.